Characterization of variable stiffness joints for adaptive structures

This paper presents a new strategy to control the structure dynamic response via a shift of the natural frequencies obtained through using variable stiffness joints. The joints are made of shape memory polymers and are fabricated through 3D printing. Stiffness variation is activated through resistive heating which causes a phase change from a glassy to a rubbery state in order to switch the joint between a ‘locked’ (e.g. a moment connection) and a ‘released’ (e.g. pin) state. This work comprises an experimental and a numerical part: 1) dynamic mechanical thermal analysis (DMTA) has been carried out to characterize the viscoelastic behavior of a 3D printed SMP specimen; 2) the dynamic response of a 2-floor planar frame equipped with four variable stiffness SMP joints is simulated through transient analysis. Numerical results show that through joint stiffness control, the fundamental frequency shifts up to 19% causing a drastic reduction of the dynamic response under resonance loading. A comparison between variable stiffness joints with viscoelastic and only-elastic behavior shows that viscoelasticity increases mechanical damping up to 4.7 times during the transition phase.

Zingoni, Alphose
Published in:
Proceedings of the 7th International Conference on Structural Engineering, Mechanics and Computation (SEMC 2019)
Presented at:
Advances in Engineering Materials, Structures and Systems: Innovations, Mechanics and Applications, Cape Town, South Africa, September 2-4, 2019
Aug 21 2019
London, Taylor & Francis

 Record created 2019-11-11, last modified 2019-12-11

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